Replace NULL with nullptr in all C++ files.

webrtc/voice_engine/test/channel_transport/udp_socket_manager_wrapper.cc

 /*
  *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 20 matching lines @@
 #endif
 }
 
 UdpSocketManager* UdpSocketManager::StaticInstance(
     CountOperation count_operation,
     const int32_t id,
     uint8_t& numOfWorkThreads)
 {
     UdpSocketManager* impl =
         GetStaticInstance<UdpSocketManager>(count_operation);
-    if (count_operation == kAddRef && impl != NULL) {
-        if (impl->Init(id, numOfWorkThreads)) {
-            impl->Start();
-        }
+    if (count_operation == kAddRef && impl != nullptr) {
+      if (impl->Init(id, numOfWorkThreads)) {
+        impl->Start();
+      }
     }
     return impl;
 }
 
 UdpSocketManager* UdpSocketManager::Create(const int32_t id,
                                            uint8_t& numOfWorkThreads)
 {
     return UdpSocketManager::StaticInstance(kAddRef, id, numOfWorkThreads);
 }
 
 void UdpSocketManager::Return()
 {
     uint8_t numOfWorkThreads = 0;
     UdpSocketManager::StaticInstance(kRelease, -1,
                                      numOfWorkThreads);
 }
 
 UdpSocketManager::UdpSocketManager() : _numOfWorkThreads(0)
 {
 }
 
 uint8_t UdpSocketManager::WorkThreads() const
 {
     return _numOfWorkThreads;
 }
 
 }  // namespace test
 }  // namespace webrtc